Non-prescription Pain Relievers

One of my favorite stories in American literature is a chapter in Mark Twain’s iconic classic, Tom Sawyer, entitled The Cat and the Pain Killer. It’s about Tom’s solution to a problem – his Aunt Polly has discovered a new medicine called Pain Killer, with which she has taken to dosing him on a daily basis, and the stuff tastes simply horrible. So Tom conceives a plan. He pretends to be fond of it, and makes a nuisance of himself asking for it, until his aunt tells him just to help himself. He does so with gusto, except that he pours the medicine down a crack in the floor instead of down his throat. All goes well, until one day when the family cat happens by as Tom is dosing the crack.

The cat, thinking everything that humans have must be good, meows plaintively until Tom decides to give him a dose. After receiving it, the hapless animal goes on a tear about the house, doubtless brought on by the terrible taste and the considerable alcoholic content of the Pain Killer. Tom’s Aunt Polly forces him to confess what he did, and castigates him for cruelty to animals, after which Tom points out that what is cruel to a cat might just be cruel to a boy as well. His aunt relents and Tom gets dosed with the Pain Killer no more

While the story is poignant, it illustrates well the state of the pharmaceutical industry in the 19th century. Drugs were unregulated, so anyone was free to mix up a concoction to treat any ailment and hawk it to the public. Brews such as Pain Killer were common, and probably effective too, as they most likely contained liberal amounts of alcohol and opiates. Too frequent use for minor ailments like headaches or muscle pain from over exertion were likely to lead to a far more serious problem. However, non-addictive drugs to suppress pain simply did not exist.

In 1897, a German chemist named Felix Hoffman, who was working for Bayer, synthesized what was to become the first wonder drug of the new century, acetylsalicylic acid, also known as aspirin. In addition to being quite an effective pain reliever, aspirin also had antipyretic (fever-reducing) properties. Many years after its invention, aspirin was also found to be effective in the treatment of and protection against certain kinds of heart attacks because of its anti-clotting and anti-inflammatory properties. However, aspirin was not a perfect drug – its side effects included stomach upset and a tendency to cause stomach ulcers with chronic use. It was also implicated in a rare but potentially fatal disorder called Reye’s syndrome. Reye’s syndrome typically occurs during recovery from a viral disease such as chicken pox or flu, and a causal link to aspirin use has been found. This has caused aspirin to fall out of favor as the go-to drug for relief of minor pains.

About the same time as the invention of aspirin, two chemists a class of chemicals known as aniline derivatives were being investigated for antipyretic effects. In 1877, a German physician, Joseph von Mering, tested an aniline derivative, paracetamol, in patients, and found it effective. However, it was not until the 1950’s that this chemical was effectively marketed. In addition to its effectiveness as a fever reducer, paracetamol was also found efficacious as a pain reliever. In the United States, paracetamol is also called acetaminophen. The most famous brand name of this drug is Tylenol.

Many doctors and patients prefer acetaminophen for pain relief because it does not irritate the stomach as other pain relievers do. It also has few interactions with other drugs, making it a popular choice for patients on a multi-drug regimen. However, acetaminophen can potentially cause serious and fatal cases of liver failure if taken at too high a dose, or in combination with alcohol. Moreover, the therapeutic dose of acetaminophen (the dose that has a beneficial effect) is quite close to the toxic dose, at which liver damage occurs. As little as 25% over the recommended maximum dose taken over a few days can cause liver failure. This is a problem because some nonprescription formulations contain acetaminophen, such as multi cold symptom relievers and headache powders. Many people do not read labels carefully, and end up taking a dangerous dose of acetaminophen if using two products simultaneously. Acetaminophen is also contained in formulations of more powerful pain relievers such as Percocet and Vicodin, so adding extra acetaminophen when taking drugs like these is also dangerous.

Another class of non-prescription pain killers are the non-steroidal anti-inflammatory drugs, or NSAIDS. Examples of these include ibuprofen (brand names Motrin and Advil), and naproxen sodium (Aleve). Aspirin is also considered an NSAID, but is usually considered in a class by itself. The principal side effects of these drugs are gastrointestinal, and regular use has been implicated in a higher risk of heart attack or stroke.

All of these non-prescription pain killers have a similar mechanism of action – inhibition of the production of prostaglandins, which are substances produced in the body that promote inflammation.

All of these drugs have their adherents, and seem to be equally safe if used in moderation. They are surely one of the blessings of modern technology. In times past, the chronic pain that accompanied advanced age offered only the choice between constant suffering and addiction. Because of these drugs, we have a far better choice today.

Headache

Photo credit: Brandon Koger / Foter / CC BY-NC-SA

Advertisements
This entry was posted in Science and tagged , , , , , , , , , , , , , , , , , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s